HOLLYWOOD -- The “NCIS: New Orleans” origin story dates to last summer, when Gary Glasberg, the show-running executive producer of “NCIS,” was doing his annual between-seasons research on future storylines for the show. Glasberg has been with “NCIS” since 2009. Itself a spinoff (of “JAG”) and a fixture on CBS since 2003, the Washington, D.C.-set “NCIS” averaged 21.6 million viewers in the 2012-2013 TV season and is TV’s No. 1 scripted drama again this season.

“I sit down in between seasons and I look at information about the real NCIS,” Glasberg said during a recent interview at the Winter TV Tour. “I do my studying. I read the paper. I catch up on news. And one of the things I came across was the fact that (there is) a real NCIS office in New Orleans. And because of the richness of the backdrop of your city, I got excited.

“Unlike Washington, D.C., which has this tremendous NCIS presence, there's this little office that is now located at the Naval air station in Belle Chasse. For a long time it was run by one man, and now it's like three or four guys.

“The fact that there's this little office and the Navy and the Marine Corps felt the need to have it there intrigued me.”

“I went to Mark Harmon as I do every year and said, ‘I went through some stories and, hey, I came across this scenario. I’d love to try to do an episode,’” Glasberg said. “He turned to me and said, ‘Gary, that’s not a sweeps episode. That’s a new show.’

“In a matter of a few weeks, we were in with (CBS TV Studios) and the network and presented what I thought could be a series, and they were thrilled. It was just sort of hot right out of the gate.”

Glasberg has written two one-hour scripts. They’ll be filmed in Los Angeles and New Orleans in late February or early March to be aired as two “NCIS” episodes later this season. “NCIS” characters will interact with the new-show characters in the episodes, a “planted” spinoff that will be considered for CBS’ fall schedule.

“It will be two episodes of ‘NCIS’ that happen to significantly take place down there,” Glasberg said, adding that Harmon will be among the “NCIS” actors who will come to New Orleans for location shooting. “We’ll meet these new characters, but still have a story and situations going on in D.C. We’ll intercut the two, and hopefully establish characters that people embrace and feel comfortable with and that hopefully will find their way onto the fall schedule.”

More from Glasberg about “NCIS: New Orleans,” which is technically still a working title:

It’s not a sure thing to go to series.

“NCIS” has successfully spawned one spinoff, “NCIS: Los Angeles.” Now in its fifth season, the show averaged more than 17 million viewers last season. A third potential spinoff, “NCIS: Red” – introduced during a two-part episode arc on “NCIS: Los Angeles” last year – was not picked up by CBS.

But it’s got a lot of elements that would could make it a viable TV spinoff – borrowing some of the mothership show’s DNA while establishing itself as a new thing in a new place.

“What intrigued me when I was down there on the first of a few research trips … is that everything we do is there,” Glasberg said. “Not only going to Belle Chasse, but hearing about other Naval air stations, hearing about Navy SEAL training that goes on not far from there, the proximity to Pensacola, the amount of shipbuilding that's coming through the Gulf, and then the Marine reserve center.

“The stories that the agents who are currently there were sharing with me -- it's all there, and then some. I kept waiting, honestly, on the first trip, for there to be a bump, and I didn't get one. So that excites me.

“Is the backdrop of knowing that a ship can pull up along the river and (its sailors) can walk four blocks and be on Bourbon Street, and guys can go out and have a good time -- is that fun? Yes, of course. Do I think I may do that every episode? No, it's much richer and much more significant than that.

“And you have the richness of the music background and everything else that is going on in the city. They don't have that in Washington. That's what can make it different, and that's what’s going to make it fun, and that's going to give us a lightness and visually something that’s special.”

The nature of the real New Orleans NCIS office Glasberg has researched will likely give the prospective new show a different scale than the Washington, D.C.-set “NCIS.”

“The NCIS agents there have been very involved in helping me connect with people,” Glasberg said. “We’re going to reach out through them to the NOPD and the Jefferson Parish Sheriff's Office, and all the (local agencies) that in theory would come into play. What makes the NCIS office there in reality so unique is that they rely on all of these other agencies to help them. They don't have the enormous manpower that Washington does.”

Casting for the two-episode “planted” pilot/new show is not complete.

“It just started,” Glasberg said. “There's a little bit of auditioning going on. I just delivered the second script a day or two ago. Now, all the wheels are turning and all the talk is happening.”

The new show’s character descriptions have been circulated in casting circles.

The details, per CBS:

“NCIS Special Agent D. Pride – MALE, charismatic and full of life, a man who savors every moment but can be rock-solid and strong when needed.

“NCIS Special Agent C. LaSalle -- MALE, handsome, born-and-bred Louisiana, a former Sheriff’s deputy who’s been through some rough times.

“NCIS Special Agent M. Brody -- FEMALE, full of insights, no-nonsense, put together, a government employee façade on an Ivy League mind, Brody is Grace Kelly-like in her class, pomp and circumstance.

“Dr. L. Wade -- FEMALE, outspoken and seriously on her game. She’s often intentionally full of contradictions.”

“The characters have evolved a little bit (from the above descriptions), but those are basically who they are,” Glasberg said. “Now that people can read full scripts, I feel like there's a lot to these characters I hope will draw (actors) in and make them want to come do this.”

Two of the main characters are locals, Glasberg said. One is from the Midwest. Another is from New Mexico and has lived in Boston.

“I want to portray as realistically as I can the path that brings people to the city, and what makes them stay there,” Glasberg said. “There's a connection that I see in talking to people from New Orleans that you don't get from other cities. There's a connection that they have with that place that is fascinating, like a dedication to it, a symbiotic alliance. I've never seen anything like it. It’s bizarre to me.”

Given the characters’ backgrounds, Glasberg is aware of the pitfalls of attempting to re-create how we talk.

“I’m very sensitive, especially in talking to people there, (about) portraying things properly,” he said. “It’s tricky there. You’re making a television show you want to be entertaining, but I recognize there’s a right way to do things. I don’t want to mess up dialects. I just want to do things right and I’m excited to try.

“It’s such an international city. Honestly, the first thing I said after being there for little while was, ‘Why would you even bother to try to do dialects and intonations when you've got influences coming from all over the world?’”

It’s not yet known whether the spinoff would be produced on location.

For 11 seasons and nearly 250 episodes, “NCIS” has mostly faked its Washington, D.C., setting in the Los Angeles area.

“I can’t predict the future,” Glasberg said. “If it goes to series, I don’t know what that means in terms of working in the New Orleans area. Right now, I’m just focused on making two episodes that are the strongest I can make.”